Soft disposable contact lenses are commonly contained in disposable packages. As packaging adds to the overall cost of the lens, it should be made as economically as possible but without compromise to the requisite packaging criteria. The traditional blister pack packaging (shown in FIGS. 1-3) for disposable lenses (both bi-weekly and daily) consists of a polypropylene receptacle for the lens (herein after referred to as a “boat”), topped by a multi-layer film consisting of polyethylene, aluminum, a bonding agent and polypropylene. The boat is typically an injection molded plastic which has high stiffness but is capable of limited elastic deflection and includes a preformed recess. The boat is filled with a suitable storage solution, preferably saline, and receives a single lens in situ. The blister pack is then autoclaved using steam and pressure to terminal sterility. These blister packs are presented to the patient in boxes of individual packs (FIGS. 4-5) or as multiple blister strips.
The marketing objective is to present the contact lens to a patient in an aesthetically pleasing package that both satisfies the statutory requirements for sterility and stability, and allows the patient to remove the lens safely and easily. The lens must be kept hydrated while in the package. The package must be well sealed and should minimize water vapor transmission through the boat and laminated layer to maximize the shelf life and prevent drying out of the lens contained therein. During use, the user removes the laminated material from a flange formed on the boat by peeling back the cover to expose the lens immersed in a hydrating solution.
A variety of contact lens packages, particularly disposable contact lens packages including preformed blister packs, have been traditionally used. Conventional wisdom in the contact lens industry has been to provide preformed stiff packaging which protects the lens from damage from applied load. Examples of traditional blister packs are shown in: U.S. Pat. Nos. 5,704,468; 4,392,569; 5,620,088; 5,691,820; 5,823,327; 5,853,085; EP Publication No. 1 092 645; and EP Publication No. 0 129 388.
While numerous contact lens packages exist, they all traditionally include boats made of homopolymer polypropylene in order to satisfy statutory requirements for sterility. While sterility is provided by the use of homopolymer polypropylene, the resulting product is a semi-transparent boat or substrate unable to provide secondary utility.